• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.764-768
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• 2002

In this paper, a double balanced gilbert cell MMIC mixer was realized in Tachyonics SiGe HBT technology. The fabricated mixer has 17 dB conversion gain, 9.8 dB noise figure, -4.2 dBm output 1 dB compression point, -27 dBc RF to IF isolation, and the good input, output matching characteristics. It draws 10 mA from a 3 V supply. The simulation and the measured results are closer to each other, which confirms accuracy of the model library and reliability of the process.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.512.2-512
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• 1986

A mutant of bacillus subtilis with a defective cdd gene encoding deoxycytidine-cytidine deaminase(EC 3.5.4.5.) has been characterized genetically. The genetic lesion causing the altered deoxycytidine-cytidine deaminase, cdd, was mapped at 225 min on the linkage map of B.subtilis by AR9 transduction Transductional analysis of the cdd region established the gene order as trp-lys-dnaE-cdd-aroD. The cdd gene was linked 72% with the aroD and 20% with the lys.

• Natural Product Sciences
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• v.2 no.2
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• pp.130-136
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• 1996

Evaluation of plant extracts that might inhibit hepatitis B virus (HBV) replication was performed to find potent anti-HBV agents. Eighty-five species of plants from forty-three families were tested for their anti-HBV activities using HBV-producing HepG2-derived 2.2.15 cells. The anti-HBV activity of plant extracts was measured by slot blot hybridization technique and cytotoxicity was determined by crystal violet staining procedure. All plants were extracted with methanol and the extracts were partitioned into n-hexane, ethyl acetate and aqueous layer. The ethyl acetate fractions of Rhus verniciflua $(stem:\;EC_{50},\;8.2{\mu}g/ml;\;CC_{50},\;9.4{\mu}g/ml)$, Gastrodia elata $(root:\;EC_{50},\;17.7{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, Raphanus sativus $(seeds:\;EC_{50},\;17.3{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, and Angelica gigas $(root:\;EC_{50},\;8.3{\mu}g/ml;\;CC_{50},\;15.6{\mu}g/ml)$ revealed the anti-HBV activity in 2.2.15 cell culture system and these fractions are under the process of further sequential fractionation by column chromatography to find the active principles against HBV.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.245-253
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• 2005

This study was carried out to determine the optimum EC supply by accumulation amount of solar radiation in closed system. EC concentration of drainage was higher than that of supply. The higher EC concentration of supply was, the lower pH of drainage was. It was no difference in the quality of cut rose 'Nobles' (Rosa hybrida), stem length, stem diameter, leaf number, petal length, and petal diameter by EC treatment by season. The yield was higher about $6\%$ in treatment of EC $1.3dS{\cdot}m^{-1}$ in April and May, about $10\%$ in treatment of EC $10dS{\cdot}m^{-1}$ in June, July and August, and about $10\%$ in treatment of EC 1.0 or $1.3dS{\cdot}m^{-1}$ in September and October than the others. In general, the yield of the cut rose was higher in treatment of (B) EC 1.3 mS/cm in spring, EC $1.0dS{\cdot}m^{-1}$ in summer, EC $1.3dS{\cdot}m^{-1}$ in autumn, and EC$1.6dS{\cdot}m^{-1}$ in winter.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.45-46
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• 2009

This study was carried out to identify the changes of EC during desalinization due to flooding in newly reclaimed saline soil. To do this, experimental plots were made of rotary tillage+water exchanging plot, flooding plot and rainfall flooding plot. In rotary tillage+water exchanging plot, drainage, rotary tillage and flooding were conducted at the interval of 7 days. In rotary tillage+water exchanging plot and flooding plot, plots were irrigated at the height of 10 cm. After 38 days desalinization, changes of EC values at top soil (0~20 cm) were as follows. In rotary tillage+water exchanging plot, EC decreased from $21.38dS\;m^{-1}$ to $2.16dS\;m^{-1}$ and in flooding plot, EC decreased from $13.97dS\;m^{-1}$ to $2.22dS\;m^{-1}$. In rotary tillage+water exchanging plot and flooding plot, EC values decreased below the EC criterion ($4.0dS\;m^{-1}$) of saline soil. In rainfall flooding plot, EC values decreased or increased according to amounts of rainfall and rainfall time. After 38 days, EC decreased from $16.7dS\;m^{-1}$ to $12.35dS\;m^{-1}$. In flooding plot, changes of EC due to soil depth were investigated. After 38 days desalinization, changes of EC due to soil depth were as follows. At 0~10 cm depth, EC value decreased from $13.08dS\;m^{-1}$ to $0.74dS\;m^{-1}$ (94.3% of salt was desalinized). At 10~20 cm depth, EC value decreased from $14.80dS\;m^{-1}$ to $3.69dS\;m^{-1}$ (75.2% of salt was desalinized). At 20~30 cm depth, soil was desalinized slowly compared with upper soil, EC value decreased from $13.57dS\;m^{-1}$ to $6.93dS\;m^{-1}$ (48.9% of salt was desalinized).

• BMB Reports
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• v.43 no.1
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• pp.62-68
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• 2010

Matrix Metalloproteinases (MMPs) are a family of zinc-endopeptidases which can degrade extracellular matrix (ECM) components and play important roles in a variety of biological and pathological processes. 6,6'-bieckol isolated and characterized from an edible marine brown alga Ecklonia cava (EC), according to the comprehensive spectral analysis of MS and NMR data. Here the influence of 6,6'-bieckol on expressions of MMPs was examined by zymography and western blot analysis via human fibrosarcoma cell line (HT1080). It is shown that 6,6'-bieckol significantly down regulated the expressions of MMP-2 and -9 in dose-dependent manner. The influence of 6,6'-bieckol on the cell viability and cell behavior of HT1080 cells were also investigated, our dates shown that it suppressed the migration and 3D culture in HT1080 cells. Meanwhile, we explored several signal pathways which may contribute to this process, and found the suppressing of MMPs expressions in HT1080 cells might be due to the suppression of NF-${\kappa}B$ signal pathway.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.536-539
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• 1988

A mutant of Bacillus subtilis with a defective cdd gene encoding deoxycytidine-cytidine deaminase (EC 3.5.4.5) has been characterized genetically. The genetic lesion, cdd, causing the altered deoxycytidine-cytidine deaminase was mapped at 225 min on the linkage map of B. subtilis by AR9 transduction, Transductional analysis of the cdd region established the gene order in clockwise as trp-lys-cdd-aroD. The cdd gene was linked 72% with the aroD and 20% with the lys.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.9
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• pp.801-811
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• 2021

Lightning can deliver large amounts of energy to the aircraft in a short period of time, resulting in catastrophic consequence. In particular, lightning strikes accompanied by high temperature heat and current can damage aircraft surface and internal electronic equipment, seriously affecting flight safety. Lightning experiments to analyze this effect use a Component A waveform with a maximum current of 200 kA as specified in SAE ARP 5412B. However, the actual lightning occurs mostly below 35kA and lightning indirect tests are conducted by reducing waveforms to prevent damage to internal electronic equipment. In this study, we examine previous methods to plot the Component A reduced waveform and identify their limitations. We then propose a new method to plot the reduced waveform based on adjusting the correction factor of the aircraft lightning Component A waveform. Finally, the electromagnetic analysis software EMA3D was used to compare the internal induced current size reduction ratio of the internal cable harness of the EC-155B helicopter.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.798-803
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• 1999

Prolyl endopeptidase [PEP; EC 3.4.21.26], a serine protease which is known to cleave peptide bonds on the carboxy side of a proline residue, plays an important role in the degradation of proline-containing neuropeptides that have been suggested to participate in learning and memory processes. An abnormal increase in the level of PEP, which can lead to generation of $A{\beta}$, is also suggested to be involved in Alzheimer's type senile dementia. In the course of screening PEP inhibitors from Basidiomycetes, the mushroom Polyozellus multiplex exhibited a high inhibitory activity against PEP. Two active compounds were isolated from the ethyl acetate soluble fraction by consecutive purification, using silica gel, Sephadex LH-20, and Lobar RP-18 chromatography. The chemical structures of these compounds were identified as thelephoric acid and 12-acety1-2,3,7,8-tetrahydroxy-[12H]-12-hydroxymethylbenzobis[I.2b,3.4b'] benzofuran-11-one (kynapcin-9) by spectral data including UV, IR, MS, HR-MS, $^1H-,{\;}^{13}C-$, and 2D-NMR. The $IC_{50}$ values of the thelephoric acid and kynapcin-9 were 0.157 ppm (446nM) and 0.087 ppm (212nM) and their inhibitor constants ($K_i$) were 0.73ppm ($2.09{\;}\mu\textrm{m}$) and 0.060 ppm (146 nM), respectively. Furthermore, they were non-competitive with a substrate in Dixon plots.

• KSBB Journal
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• v.9 no.1
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• pp.55-62
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• 1994

Glucose oxidase(EC 1.1.3.4) was purified to electrophoretic homogeneity from Aspergillus niger by a combination of ammonium sulfate fractionation, ion exchange chromatography, and ultrafiltration. Two active fractions A and B, of glucose oxidase were obtained from the hydrophobic chromatography on phenyl sepharose CL-4B. The enzyme A and B were glycoproteins with the same denatured molecular weight of 78, 000 and had specific activities of 2, 191 and 1, 273-units/mg proteins, respectively. But the two enzymes showed differences in native molecular weight that was measured by HPLC gel filteration, maximum absorbtion wavelength and isoelectric point. The enzyme A oxidized $\beta$-D-glucose only and was resistant to sodium dodecyl sulfate. Activity optimum was found at $30^{\circ}C$ and pH 3.5. Also the enzyme A was inhibited greatly by $Hg^{2+}$(10mM). The results of chemical modification experiments suggested that cysteine and cystine residues might be involved in the active site of the enzyme A.